I doubt that the therapist is lying. I have heard one therapist saying she does that too - not set appointment after vacation but just call when she's back. I think this takes away from the sense of stability and security that the therapeutic relationship should provide. Not to mention that as a therapist such an arrangement would cause ME anxiety, even if some clients may manage it well. I just think that things need to be talked about beforehand, not left open like that.

On the other hand, I think what matters the most is how you feel about it and what you do. If you want to work with this therapist and feel trust between the two of you, perhaps try telling him how this has impacted on you and what you need. Perhaps this could help you both. But if you feel it's not worth it, perhaps you might like looking for another therapist rather than trying with this one if it doesn't feel right.

Whatever you choose to do, I hope you know that the way therapists manage their vacations has nothing to do with you. And if it does (which I highly doubt), then I think that therapist has serious issues, not you ... Just my thoughts.